1. Field of the Invention
The present invention relates to glass processing equipment. Specifically, the invention relates to a glass cutting line having integral offal storage and retrieval system.
2. Background Information
Glass processing equipment includes glass cutting lines. Glass cutting lines are well known in the industry and some typically critical components of a glass cutting line includes a cutting table having a movable cutting head (such as though an XY positioning system) configured to cut glass work pieces on the table. Glass cutting tables are available from the assignee of this invention, Billco Manufacturing, Inc. (Billco) and others. Examples of glass cutting lines are described in U.S. Pat. Nos. 5,791,971, 6,463,762 and 6,810,784, which are incorporated herein by reference.
Within the meaning of this application glass cutting table is a glass processing apparatus that is configured to score or cut glass work pieces according to predefined patterns. The cutting patterns are generally prepared by a glass optimizing system, such as developed by Billco and available from HP3 Software under the Batch Ban® trademark. An XY cutting head is a glass cutting or scoring device, e.g. cutting wheel, which is movable within the XY plane to cut the work piece, typically by having a bridge extend across the table for movement along one axis and a carriage moveable along the bridge in the second axis. The cutting head generally can also move into and out of engagement with the work piece along a third (z) axis, and are generally numerically controlled according to the predetermined cutting pattern. It is possible, but less common, to have a glass cutting head moveable only across the table (the X or Y direction, depending on the orientation), but such a cutter is less common.
It is common to have a feeding table in front of the cutting table of a cutting line and a break out table adjacent the cutting table. One common feeding table is a tilt feeder. A tilt feeder generally includes a tilt loader table, a tilt loader table conveyor, and a pivoting tilt loader. The pivoting tilt loader receives glass work pieces, such as from a gantry crane from a variety of glass storage racks. The pivoting tilt loader will typically receive the work pieces in a generally vertical orientation and delivers the glass work pieces to the tilt loader table in a general horizontal orientation, whereby the tilt loader table conveyor transports the glass work pieces to the cutting table. It has been known, and is generally common, to place the entire tilt feeder on tracks to move the feeder toward where the work pieces can be loaded onto the feeder. Other feeder tables are known in the art other than a tilt loader.
Glass work pieces within the meaning of this application references all glass work pieces throughout the glass processing process, including stock lites, individual cut pieces and remnant or offal pieces, also called offcuts. Offal glass work pieces are generally referencing the portion of a stock lite or sheet that remains after cutting one or more work pieces there from, wherein the remnant is large enough to meaningfully obtain future needed work pieces there from, whereby it is efficient to store the remnant for future use rather than scrap the unused portion. The offal is, effectively, a cut remnant that is too large to scrap. The term “offal” here is borrowed from the butchery arts, where it has a different, but somewhat analogous meaning.
Optimization Software Systems for glass cutting generally produce random size offal, offcut or remnant pieces (also referred scrap glass), at various times during the optimization process. These large offal pieces may be discarded immediately, or re-used on a future cutting layout. Historically, the problem with re-using the remnant pieces is where to store them until the Optimization software determines an appropriate cut piece layout for each offal size. Manual racking and re-loading of the offal pieces takes time, requires storage space, and is prone to glass scratching during handling.
When an offal piece is generated, special handling is required on many glass types to avoid destroying the offal piece. Manual handling may be inefficient and inappropriate for many glass types. In view of these restrictions several offal storage and retrieval systems have been proposed in the art.
Many of these offal storage and retrieval systems require significant modifications to the cutting line by placing a separate offal handler and a separate work piece storage and retrieval device. The storage devices can be a “cassette type” storage device. A cassette type storage device can be defines herein as a storage device which receives work pieces from the handler and delivers work pieces to the handler from any of a plurality of storage locations within the cassette device. The control system will designate a storage location for a particular stored piece so the offal work piece can be recalled later when needed.
See for example U.S. Pat. No. 7,217,077 which discloses a separate storage system for use next to a glass processing line having a loading table, a glass cutting table and a breakout table. The storage system comprises a first tilt table and a second tilt table. A cassette storage rack is positioned between the first and the second tilt tables. The storage rack comprises a plurality of parallel storage slots extending longitudinally within the main frame of the storage rack. The storage slots stores the glass offcuts at a substantially vertical position of less than 90 degrees with reference to the horizontal. In use, the first tilt table receives horizontally-disposed glass offcuts from the breakout table and sends it to the storage rack. The second tilt table receives previously-stored glass offcuts from the storage rack to be directed to the loading table. This system has been commercialized by Bromer, Inc.
The difficulty with the existing offcut, offal or remnant handling systems is that there is not always room to expand the glass cutting line to incorporate the system. Further, the existing systems increase the time for offal handling considerable which results in decreasing the overall efficiencies of the cutting line. In a glass cutting line the reduction of scrap can greatly improve yield and production, and the decrease in production time can also increase production. There always remains a need to improve these two characteristics of any glass cutting line.